Musculoskeletal pain conditions are the most common diagnosed medical problems among Operations Enduring Freedom, Iraqi Freedom, and New Dawn (OEF/OIF/OND) service members and Veterans, far surpassing the prevalence of other medical and mental health disorders. Chronic low back pain (cLBP) is the most common pain condition in the military, causing substantial physical and psychological suffering, reduction in force readiness, and high economic cost to the military. Identifying new safe and effective alternatives to opioids that address the physical and psychosocial dimensions of chronic low back pain is urgently needed. Yoga is one of several Tier 1 complementary modalities identified by The Army Surgeon General's Pain Management Task Force 2010 Report as priorities for DoD-VA research and possible integration. Yoga has been studied in 10 RCTs in civilian populations with cLBP suggesting it may be effective in reducing pain intensity, improving back-related function, and lowering pain medication use. Our two RCTs of yoga for predominantly minority low income men and women with moderate-severe cLBP showed similar results as well as a decrease in pain medication. Multiple differences exist between civilian and military populations with cLBP, making it necessary to adapt and test yoga for cLBP in military populations. Our proposal's primary aim is to evaluate the effectiveness of yoga for reducing pain in military personnel and Veterans with cLBP through a structured, reproducible 12-week series of hatha yoga classes, supplemented with home practice, compared to an education group. We hypothesize yoga will be clinically and statistically superior to education only. Additionally, the enormous mental health burden often shouldered by returning military personnel presents another important distinguishing factor. Thus, our secondary aim is to assess yoga's capacity to reduce post- traumatic stress symptoms (PTSS). Our third and final aim is to evaluate the cost-effectiveness of yoga for cLBP at 12 weeks and 24 weeks. The proposed RCT will (1) establish a structured reproducible yoga protocol uniquely suited to Veterans populations with cLBP and associated psychological comorbid symptoms; (2) develop web-based delivery systems to assist Veterans in practicing yoga at home; (3) increase our knowledge of the feasibility and impact of yoga for Veterans' cLBP, psychological comorbidities, and family functioning; and (4) provide a strong foundation for larger multi-site studies and implementation projects. These results will help determine whether yoga is an effective modality for addressing cLBP in a military population.